Lock for Railway Switch Actuating Devices

ABSTRACT

A lock for railway switch adjusting devices, including a locking member having a guide contour extending in the direction in which the switch is actuated and forms a locking seat projecting transversely from the guide contour; a locking lever hinged to an engaging tongue and carries, at the end remote from the tongue, an arresting bolt to be blocked at the locking seat; a guide bolt slidable in the guide contour; a hinge bolt connected to a remote tongue; a bearing block rotatable about the guide bolt axis and in which the arresting bolt, the guide bolt and the hinge bolt are journalled in a triangular configuration such that the arresting bolt and the hinge bolt are positioned on opposite sides of the guide contour and are closer to the engaging tongue than the guide bolt, and a spring that biases the remote tongue towards its remote position.

The invention relates to a lock for railway switch actuating devices.

Switches for track vehicles have switch tongues that are pivotally disposed between so-called stock rails of a switch and can be adjusted in transverse direction of the stock rails by means of the switch actuating device. In each stationary state of the actuating device, one of the two tongues engages the associated stock rail. This tongue is therefore designated as engaging tongue. The other switch tongue is designated as remote tongue because its tip end has a certain distance from the associated stock rail. The lock has the purpose to positively lock the engaging tongue in the engaging position in order to prevent the same from being separated from the stock rail, because this might cause the track vehicle to be derailed. A switch actuating device must therefore have an unlocking mechanism which unlocks the lock before the proper actuating operation may commence.

When a track vehicle approaches the switch from the branch side and the switch is not in the right position for allowing the vehicle to pass through, the switch may also be actuated by the track vehicle itself in that the wheels of the track vehicle push the tongue that has been the remote tongue heretofore into the engaging position. This process is termed “riding open” the switch. In this case, the unlocking mechanism must assure that the locked state for the initially engaging tongue is cancelled timely enough.

An example of a known lock having this function has been described in EP 0 984 882 B1.

It is an object of the invention to provide a novel lock for switch actuating devices that functions reliably and has a compact construction.

According to the invention, this object is achieved by a lock comprising: a locking member having a guide contour that extends in the direction in which the switch is actuated and forms a locking seat that projects transversely from the guide contour; a locking lever that is hinged to an engaging tongue and carries, at the end remote from the tongue, an arresting bolt adapted to be blocked at the locking seat; a guide bolt that is slidable in the guide contour; a hinge bolt connected to a remote tongue; a bearing block that is rotatable about the axis of the guide bolt and in which the arresting bolt, the guide bolt and the hinge bolt are journalled in a triangular configuration such that the arresting bolt and the hinge bolt are positioned on opposite sides of the guide contour and are closer to the engaging tongue than the guide bolt; and a spring that biases the remote tongue in the direction towards its remote position.

When the remote switch tongue and hence the hinge bolt are subject to a force that tends to push the remote tongue into its engaged position, the engaged tongue remains initially blocked in the engaged position because the arresting bolt abuts at the locking seat. Then, the bearing block is subject to a torque that has the tendency to tilt the bearing block about the axis of the guide bolt. As a result of this tilting movement the arresting bolt enters into the guide contour so that it is lifted off from the locking seat. In this process, the spring may yield to a certain extent and thereby enable the hinge bolt to move in accordance with the tilting movement of the bearing block.

When the tongue that was initially the engaging tongue returns into the engaging position, the spring assures that the bearing block is tilted in opposite direction. In this way, it is assured that the arresting bolt abuts again at the locking seat and reliably locks the engaging tongue.

Useful details of the invention are indicated in the dependent claims.

An embodiment example will now be explained in detail in conjunction with the drawings, in which:

FIG. 1 is a schematic cross-section of a switch and a related switch adjusting device;

FIG. 2 is a top-plan view of the adjusting device shown in FIG. 1; and

FIGS. 3 to 5 are sectional views analogous to FIG. 1, for different operating states of the adjusting device.

FIG. 1 shows a switch 10 for truck vehicles and a lock 12 of an associated switch adjusting device. The switch has two stock rails 14, 16 and two switch tongues 18, 20. In the condition shown in FIG. 1, the tongue 18 engages the stock rail 14 (engaging tongue), whereas the tongue 20 is remote from the stock rail 16 (remote tongue).

The lock 12 has a locking member 22 that is disposed stationary between the stock rails 14, 16 and forms a guide contour 24 that extends in transverse direction of the stock rails. The guide contour 24 is formed by a slot that extends straight in a wall of the locking member 22 for the largest part of its length and is widened at one end, on the left side in FIG. 1, so that it forms a locking seat 26 for an arresting bolt 28, the locking seat projecting transversely from the guide contour 24. The arresting bolt 28 is mounted on a free end of a Z-shaped angled locking lever 30 the opposite end of which is connected to the engaging tongue 18 by a hinge 32. Thus, the locking lever 30 and the arresting bolt 28 engaging the locking seat 26 assure that the engaging switch tongue 18 is positively locked in the engaged position. As the axis of the hinge 32 extends horizontally and the locking seat 26 is formed at the lower side of the guide contour 24, the own weight of the locking lever 30 helps to reliably trap the arresting bolt 28 is in the locking position.

The arresting bolt 28 is held in a bearing block 34 that also accommodates a guide bolt 36 and a hinge bolt 38. The hinge bolt 38 establishes a hinge connection of the bearing block 34 with a link 40 that is again connected to the remote tongue 20 via a hinge 42.

The axes of the arresting bolt 28, the guide bolt 36, and the hinge bolt 38 form a triangle. The guide bolt 36 is slidably guided at the guide contour 24. Relative to the guide bolt 36, the arresting bolt 28 and the hinge bolt 38 are offset towards the engaging tongue 18, and they are disposed on opposite sides (above and below) the centre axis of the guide contour 24.

Halfway between the hinge bolt 38 and the hinge 42, the link 40 has a downwardly projecting lug to which a spring 48 is connected via a joint 46. In the example shown here, the other end of the spring 48 is connected to a drive system, which has not been shown, of the switch actuating device via a control rod 50.

The entire lock 12 is accommodated in a box-like casing 52 that is disposed below the stock rails 14, 16 and has slightly elevated side walls in the part that is located between the stock rails, and the locking member 22 is held between these side walls.

As can be seen in the plan view in FIG. 2, the lock 12, in its entirety, has a symmetric construction, the plane of symmetry being defined by the locking lever 30 and the link 40. When seen in plan view, the locking member 22 has a C-shaped configuration with side walls disposed symmetrically relative to the locking lever 30, and with slots that define the guide contour 24 being formed in these side walls. Optionally, the slots may be formed with congruent shapes in the walls of the casing 52, so that the casing 52 may also be considered as part of the locking member. The arresting bolt 28 passes through the entire casing 52. In FIG. 2, its central part is hidden behind the overlaid hinge bolt 38. Due to the symmetric construction, each of the bearing block 34 and the guide bolt 36 are formed by two separate parts disposed on opposite sides of the plane of symmetry. Each part of the guide bolt 36 passes through the guide contour 24 and is supported in the corresponding part of the bearing block 34. The hinge bolt 38 connects the link 40 with the two parts of the bearing block 34 but does not fully reach up to the walls of the locking member 22 in which the guide contour 24 is formed.

The spring 48 is also formed by two symmetrically arranged spring members that are connected to the common joint 46. The opposite ends of these spring members are connected to the control rod 50 by a shaft 54 that is guided in elongated holes (not shown) in the walls of the casing 52.

It shall now be explained how the lock 12 is unlocked when the switch is ridden open, i.e. when a track vehicle pushes the remote tongue 20 in the direction of the associated stock rail 16. Then, a tensile force that is directed to the right side in FIG. 1 is transmitted to the link 40 via the hinge 42. The spring 48 is a tension spring that may yield under this force so that the joint 46 may be displaced further to the right in FIG. 1. The hinge bolt 38 that is supported in the bearing block 34 is also subject to a rightward tensile force. However, the bearing block 34 cannot yield to this force because it supports also the arresting bolt 28 that is still trapped at the locking seat 26. Consequently, the engaging tongue 18 remains preliminarily blocked in the engaged position.

However, the tensile force exerted upon the hinge bolt 38 creates a torque that has the tendency to tilt the bearing block 34 clockwise in FIG. 1. As the arresting bolt 28 is caught at the locking seat 26 and the guide bolt 36 that is also supported in the bearing block 34 engages the lower edge of the guide contour 24, the bearing block 34 and the hinge bolt 38 tilt about the axis of the guide bolt 36. This causes the arresting bolt 28 to be levered upwardly and to clear the locking seat 26. The guide bolt 36 being slideable in the guide contour 24, a translational movement towards the right in FIG. 1 may be superposed with the tilting movement of the bearing block 34, so that the arresting bolt 28 does not have to move towards the left during the tilting movement, in which case it would interfere with the locking lever 30 that is supported at the tongue 18. As the case may be, a certain bearing play and a certain play of the guide bolt 36 in the guide contour 24 may help avoiding that the bearing block 34 gets jammed in the process described above.

FIG. 3 shows the condition in which the bearing block 34 has been tilted so far that the arresting bolt 28 has cleared the locking seat 26 and is now accommodated in the guide contour. The exact shape of the locking seat 26 may therefore be seen more clearly in FIG. 3. The remote tongue 20 and the link 40 have slightly moved to the right in FIG. 3. Moreover, the link has slightly been tilted about the hinge 42 because the bearing block 38 has been lifted. The joint 46 to which the spring 48 is connected has also been displaced somewhat to the right. As the control rod 50 has not been actuated in the process of riding open the switch, the spring 48 has been expanded slightly.

Now, in the condition shown in FIG. 3, the locked state of the engaging tongue has been cancelled, so that this tongue may now be entrained rightwards in the further course of process of riding open the switch.

FIG. 4 illustrates the condition at the end of this process. The tongue 20 now engages the stock rail 16 whereas the tongue 18 is separated from the stock rail 14. The guide bolt 36 has been displaced to the right end of the guide contour 24. The arresting bolt 38 engages the straight upper edge of the guide contour 24 with its ends and has thereby prevented the bearing block 34 from being tilted further, so that the bearing block 34 has made a pure translational movement. The spring 48 is expanded to a high degree and is thus under considerable tension. When the track vehicle has left the switch, the restoring force of the spring 48 may cause the switch to return to the initial position shown in FIG. 1. In the end phase of this movement, the arresting bolt 28 will again fallin at the locking seat 26, partly because of the own weight of the locking lever 30 but mainly because of the torque that the bearing bolt 38 exerts upon the bearing block 34 and now acts in counter-clock sense.

When the arresting bolt 28 has reached again the locking position shown in FIG. 1, the central axis of this arresting bolt 28 is slightly lower than the lower edge of the guide contour 24. Consequently, when the tongue 18 exerts a rightwardly directed force onto the arresting bolt, the latter cannot be lifted over the locking seat 26 but will be held at the locking seat 26 by a self-locking effect. In the example shown, this self-locking effect is enhanced by the fact that the locking lever 30 has a Z-shape, so that a rightwardly directed force that acts upon the hinge 32, together with the resisting force of the locking seat 26, creates a torque in clock-sense which presses the locking bolt 28 deeper into the recess at the end of the guide contour 24 that forms the locking seat 26. However, this shape of the locking lever 30 has the consequence that the locking bolt 28 must slightly move to the right in the unlocking process. The shape of the locking seat 26 may be selected such that, on the one hand, it permits this movement, but on the other hand assures the self-locking effect when the force is introduced via the locking lever 30 and the locking bolt is not lifted by the tilting movement of the bearing block 34.

FIG. 5 illustrates the case that the switch is not ridden open but is actuated actively by means of the drive system (not shown) that acts upon the control rod 50 and pushes this control rod 50 towards the right in FIG. 5. In this example, the spring 48 is configured such that, in the initial condition shown in FIG. 1, the windings of the spring are in block-engagement, so that the spring may transmit thrust forces. Then, the force of the control rod 50 is transmitted via the spring 48 and the joint 46 and further via the link 40 to the bearing bolt 38. Then, the locked state may be cancelled in the same way as has been described above in conjunction with FIGS. 1 to 3. Subsequently the tongue 20 is pushed into the engaged position by means of the control rod 50 and the spring 48.

With the lock 12 that has been shown here, it is not possible, however, to lock the tongue 20 in the engaged position. If this is desired, it is possible, however, to provide a second lock for the tongue 20, this second lock having the same construction as the lock 12 that has been described here but is arranged mirror-symmetrically thereto (except for the spring 48 and the control rod 50). Then, however, the springs 48 should be configured such that, in the condition shown in FIGS. 1 and 5, their windings are not in block-engagement but in a neutral position permitting the spring to be both, expanded and compressed, so that it is also possible to ride the switch open when the tongue 20 is the engaging tongue. 

What is claimed is:
 1. A lock for railway switch adjusting devices having an engaging switch tongue and a remote switch tongue, comprising: a locking member having a guide contour that extends in a direction in which the switch is actuated and forms a locking seat that projects transversely from the guide contour; a locking lever that is hinged to the engaging switch tongue and carries, at an end remote from the engaging switch tongue, an arresting bolt adapted to be blocked at the locking seat; a guide bolt that is slidable in the guide contour; a hinge bolt connected to the remote switch tongue; a bearing block that is rotatable about the axis of the guide bolt and in which the arresting bolt, the guide bolt and the hinge bolt are journalled in a triangular configuration such that the arresting bolt and the hinge bolt are positioned on opposite sides of the guide contour and are closer to the engaging switch tongue than the guide bolt; and a spring that biases the remote switch tongue in a direction towards a remote position thereof.
 2. The lock according to claim 1, further comprising a hinge that connects the locking lever to the engaging switch tongue, and the arresting bolt and the hinge are disposed on opposite sides of a central axis of the guide contour.
 3. The lock according to claim 1, wherein the lock has a symmetric configuration about a plane of symmetry with respect to the locking lever and wherein said guide contour includes first and second guide contours disposed on both sides of said locking lever.
 4. The lock according to claim 3, wherein each of the bearing block and the guide bolt are formed by two parts disposed on opposite sides of the plane of symmetry.
 5. The lock according to claim 1, further comprising a link which connects the hinge bolt to the remote switch tongue, and wherein the spring is supported at one end thereof by the link.
 6. The lock according to claim 5, wherein the spring is arranged in a plane that is offset relative to the guide contour and wherein the link includes a lug that projects from the link approximately at a center thereof and the one end of the spring is supported at the lug.
 7. The lock according to claim 1, wherein the spring is configured to be expanded to an amount that corresponds to a range of displacement of the switch tongues. 